<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../react资料_stu//依赖包/react.development.js"></script>
    <script src="../react资料_stu//依赖包/react-dom.development.js"></script>
    <script src="../react资料_stu//依赖包/babel.min.js"></script>
</head>
<body>
    <div id="app"></div>
    <script type="text/babel">
       /* 
      创建Refs
        Refs 是使用 React.createRef() 创建的，并通过 ref 属性附加到 React 元素。在构造组件时，会把当前书写ref的DOM交给创建的iptEle保管,放在它的current属性上
        创建一个Refs只能存放一个DOM
    */
   class Parent extends React.Component{
    iptEle=React.createRef();
    render(){
        return (
            <div>
                <input type="text" ref={this.iptEle}/>
                <button onClick={this.handle}>点我弹出用户输入的内容</button>
                </div>
        )
    }
    handle=()=>{
        console.log(this);
        const {value}=this.iptEle.current;
        alert(value)
    }
   }
   ReactDOM.createRoot(document.getElementById('app')).render(<Parent/>)
    </script>
</body>
</html>